[Mobile Master Tech]

BBP, yes-weird we have some of the same heatsource problems.

Do you have any heat transfer plates on your pex? HUUUUUGE difference compared to staple up/suspended. I call straight staple up worthless and pex with transfer plates pretty good. My system can keep up when water temps are 125F.

Also, since my AC blower runs slowly any time the main zone is on, I added a water/air HX after it using the return water from the zone to prevent cold drafts from the air movement. It doesn't add a lot of BTUs since it sees 100-110F return water and then only after the water has made a complete lap through that zone. This way the floors always warm first, the air doesn't blow cold for long, my air is always filtered, and there is a bit more output if the zone has a long duty cycle.

Yep on sealed combustion-you're creating a cold draft and possibly negative pressure/CO poisoning if you sealed up the house tight without it.

Yep on equipment within envelope. My winter gas usage with 2 scorched air furnaces, one of them in the attic, was 300-350 therms/mo, heating 2 stories. Now it is 150-200 therms/mo even though I am heating 3 stories plus the garage!

You certainly insulated the h**l out of it! I have R13 walls, R30 ceilings(for now), air filled double pane aluminum frame windows with no low-e (for now) and zero slab/basement wall insulation (for now).

Thanks for the timer idea! Will use it while away until I get the new heat source done. Won't run it regularly, as Murphy says it would probably cycle off while I was taking a shower....